On Wednesday, EPA published certain amendments to the Mercury and Air Toxics Standards in the Federal Register. EPA describes most of the changes as “technical corrections,” but there is one important substantive change. EPA has deleted the affirmative defense for violations caused by equipment malfunctions.

The change follows EPA’s 2015 SIP call requiring states to delete affirmative defenses for violations related to startup, shutdown, or malfunction events. As we noted then, the culprit is the decision in NRDC v. EPA, which held that EPA did not have authority to create such affirmative defenses.

As before, EPA has emphasized that it has sufficient enforcement discretion to take SSM issues into account. It also noted that alleged violators may still raise SSM issues with the courts, should they face citizen enforcement, and that the courts similarly have discretion to consider SSM events.

EPA’s argument may be cold comfort to generators, but the agency’s hands really were tied here.